The present invention generally relates to the acquisition and projection of ultra-wide field-of-view images on a spherical or near-spherical screen that wraps around viewers to provide a visually immersive effect.
The present invention is preceded by a century of improvements to cinema systems providing a progressively wider field of view, particularly in the horizontal dimension. Such advancements include xe2x80x9cCineramaxe2x80x9d, a 3-projector, edge-abutted system which was later replaced by single-projector 70 mm film formats including xe2x80x9cTodd-AOxe2x80x9d, and more recently, the xe2x80x9cIMAXxe2x80x9d and xe2x80x9cIMAX Domexe2x80x9d formats. While 70 mm film can produce an impressive image that is large, bright and high-resolution, it remains quite expensive to produce, distribute and project such films. xe2x80x9cIMAX Domexe2x80x9d theaters utilize spherical screens to provide the widest possible field of view images.
More recently, pioneering work has been performed using video projection to cover ultra-wide field-of-view screens that are spherical or near spherical in form. To this end, the xe2x80x9cImmersaVision(trademark)xe2x80x9d video projection format (available from Spitz, Inc.) has been developed, allowing seamless ultra-wide field-of-view images to be projected onto compound surfaces such as dome, cylinder or torus screens. The xe2x80x9cImmersaVision 200xe2x80x9d format, shown in FIGS. 1 to 3, currently produces a 200xc2x0 horizontal by xc2x130xc2x0 vertical field-of-view image on a spherical screen using three CRT video projectors which are edge-blended using Panomaker units, for example, and which are mapped using extended geometry adjustments provided by Barco NV, BR909 CRT projectors, for example. Graphic material is originated in an equidistant cylindrical mapping using an 1800xc3x97486 rectangular pixel image plane (true 10:3 aspect ratio), as represented in FIG. 4. The image is then broken into three overlapped 720xc3x97486 pixel (CCIR-601 format) video sub-frames for storage and playback. Upon playback, the sub-frames must be processed to provide feathering of the overlapped edges (edge-blending), and must be geometrically mapped to the spherical screen surface.
While such an approach provides an adequate display, CRT projectors cannot provide the brightness required of theatrical systems, and edge-blended systems remain expensive and problematic. Such systems inevitably suffer some image degradation within the blend regions, and the need to break the single 10:3 image into sub-frames complicates the post-production process. With the use of alternative projection technologies, such as the JVC Digital Image Light Amplifier (D-ILA), liquid crystal displays (LCD) and digital light processing (DLP) using micro-mirror devices, it would be possible to achieve greater brightness. The available technologies, however, including DLP, LCoS (liquid crystal on silicon), LCD and others must provide highly accurate image mapping and color matching between projectors, which is an expensive and difficult process. Also, edge-blending is problematic in that image quality is compromised in the edge-blended areas due to imperfect geometric mapping, gamma and color mismatch between projectors, etc.
The present invention provides a novel full-motion graphics format enabling acquisition and projection of ultra-wide field-of-view images. Such images are viewed on a spherical or near-spherical screen that wraps around the viewers to provide a visually immersive effect. To this end, ultra-wide field-of-view images are acquired using a novel lens system in conjunction with standard high-resolution video cameras or film cameras, permitting the images to be stored on standard digital or film media. The acquired images are then relayed onto a curved screen using a correspondingly configured, novel projection lens system, in conjunction with a standard high-resolution video projector or film projector. Further, in accordance with the present invention, a unique, manufacturable screen design is provided that complements the image format to provide a complete end-to-end imaging and projection system. An important and distinguishing feature of the present invention is that the images are projected onto a spherical or curved screen from a projection point which is approximately one radii behind dome center (the radial center of the spherical or near-spherical screen).
In its preferred embodiment, the system of the present invention uses a single film or video projector to produce an ultra-widescreen format, permitting a single high-performance, high-definition film or video projector to replace the three separate projectors of the prior systems. As a result, problematic edge-blending and precise geometric overlap are no longer required. Such a system is enabled using a xe2x80x9cfisheyexe2x80x9d or xe2x80x9comnixe2x80x9d projection format. Unlike previous fisheye and omni projection formats that place the projection lens toward the center of the spherical screen, however, the system of the present invention places the projector one radii behind the center of the spherical screen, providing a total projection distance of one screen diameter from the screen surface.